Remote control for rolling-mill screw downs



July 3, 1928.

D. R. FRANCIS REMOTE CONTROL FOR ROLLING MILL SCREW DOWNS Filed June 21, 1927 //V l/E/V TOR D/7N/1. R Fem/e15 3 B y I g E ATTORNEYS 3 Sheets- Sheet July 3,1928. 1,676,180

D R. FRANCIS REMOTE CONTROL- FOR ROLLING MILL SCREW DOWNS Filed June 21, 1927 5 Sheets-Sheet 2 I l/VI/E/VTOR JEN/EL R. Fem/as 7 ATTORNEYS July 3, 1928. v 1,676,180 D. R. FRANCIS REMOTE CONTROL FOR ROLLING MILL SCREW DOWNS Filed June 21, 1927 3 Sheets-Sheet 3 l/Vl/E/VTUR DEN/E1. Fen/v05 A .TTOR/VEKS tiara nanrnr. a. answers, or warnnnnnrr, conuno'rrcnr, assren'on we run warnnnonr 'roon renews, on warnnnunrz, oonn'ncrrcnr,aconnonarron or oonnnorronrr.

EEMGTE CQNTEQL non. RQIQLINbl-BKILL SCREW DQWhTfi.

' application filed lane 21,

This invention relates to remote controls 'for rolling mills. In the'operation of rolling mills, such as are used for rolling steel to form rods, sheets, etc., it isof the utmost importance that the distances between the rolls be adjusted with great accuracy, in order that the final product of the rolling will be of the proper dimensions,the permissible variations from the desired dimensions being in many cases but only a few thousandths of an inch. ln order to securev such great accuracy, the adjusting screws with which the mills are, usually provided and by means of which the gap between the rollers is changed, must frequently be moved as circumstances dictate. Owing to the intense heat, it is not feasible for the operator of the mill to change the position of the roll adjusting. screws directly atth'e mill. Consequently, 'it is the. usual practice-to employ some form of a'remote control for adjusting such screws. lleretofore, it has been the common practice to employ an electric motor for operatingthe screws, the operation of which motor is controlled by an electric switch located at anyconvenient point sulficiently distant from the mill, suitable gearing being imposed between the electric mo= tor and adjusting screws. One of the difficulties'ot the electric drives as just de-= scribed is due to the tendency of the electric motors-to overrun, after the control switch is opened to stop the motor, and thereforeit is exceedingly difficult to adjust the rolls with the great precision and accuracy .required.

The principal object ot-this invention is to provide a new and improved construction for a remote controlled driving g'ear especially adapted for rolling mils, by means of which the ad'ustin screws of the mills can be readily a juste with great accuracy by the simple manipulation o a single control member. I

The above and other objects will appear more fully from the following more detailed description and by reference to the -accom-- v panying drawings forming a part hereof,

and wherein Fig. 1 is a somewhat diagram-' matic front elevation of a rolling mlll equipped with a driving gear, constructedin accordance with the principles of my m vention; Fig. 2 is an enlarged front elevation of the driving gear shown in Fig. 1, a v part thereof being in section; and Figs. 3

rear... serial No. coarse;

and darerespectively anend view and a plan of the structure shown in Fig. 2.

As shown in the drawings, the rolling mill I which is indicated generally by the reference character it) isprovided with the upper and lower rolls, ll and 12 respectivel the I upper rolls being movable towards an from the lower rolls by means'ot adjusting screws in accordance with the usual construction of devices of this character. The adjusting screws have connected thereto by suitable gearing a transverse shaft 16, the construc- I driven 'by any suitable means such as an electric motor and suitable gearing which may be mounted within the housing indicated by the numeral 17. As the construction ot the drivin means for the rolls 11 I and 1.2,and the adjusting screws byimeans of which the'gap between said rolls is varied] forms no part of the present invention the constructional details of these parts ave not been shown in the drawings. -For the purpose of the present application it is sufficient to state that the rollin mill may be of any well-known construction.

Mounted on the top of thehousing 17 is a.

hydraulic speed gear which may be of the type disclosed in Letters Patent oi? the United States granted to Harvey D. Wilhams No. 925,148, June 15, 1909. As this type of hydraulic gear is well known, it is not believed necessary to illustrate the same fullyiin the drawings, therefore, l have shown the hydraulic variable speed gear diagrammatically as indicated generally by the reference character 18;

As described more. fully in the patent to .Williams above referred to, this type of hy-' draulic gear consists oil a pump-or an A-end, as it is usually called, ands B-end. The A-end is provided witha driving shaft 19 to which an electric motor or other suitable driving means may be connected'and which shafthas secured thereto a rotary barrel having a plurality of linders, parallel with the driving shaft of 'in which reciprocate pistons. Said pistons are connected with a swash plate, the angle of inclination bfv which may be varied to vary the stroke of the istons, and therefore, the output, or

no I

the amount of 'fluiddelivered by the pum for each revolution of the cylinder barre the angle of inclination of the swash plate preferably being adjusted by a controlling member 20,. operatively connected with a tilting box inwhich the swash late is rota-tably mounted. .When the tilting box and swash plate are perpendicular to the driving shaft, or in neutral position, the pistons have no stroke and no fluid is pumped. As the control member is operated to tilt the swash plate, the stroke of the pistons and consequently-the output of the pump is increased proportionately to the increase of the angle of inclination. The inclination of the swash plate in opposite directions from the neutral position causes the pump .to 011- culate the fluid in opposite directions, and as a resultproduces rotation of the B-end or motor in reverse directions. The B-end or motor is similar in construction to the pump or A-end, with the exception that the swash plate of the motor is not adjustable, but is'held'at a fixed angle of inclination. lln the drawings, if have indicated the A-end of the hydraulic gear by the reference character A and the B-end or motor by the reference character B. The shaft 19 of the pump A is driven to cause the pump to deliver fluid, which fluid passes to the motor B, produces reciprocation of the pistons of -the motor, and causes the shaft 21 of the motor to be rotated, all as described more fully in the Williams patent. In the constructional example of the installation disclosed in Figs. 1 to. 4, the variable hydraulic speed gear 18, consisting of a pump *A" and motor B, constructed as a unitary assemblage, is suitably secured to the gear housing 17 and the shaft 21 of the motor B is connected by means of a coupling 22 and reduction gearing 23 with the transverse shaft 16, the latter as heretofore described being connected by suitable gearing to the adjusting screws of therolling mill 10. In order that the adjusting screws 13 of the rolling mill maybe rotated as desired, from a distant control, the following means are provided Secured to a platform or bracket bolted to the top of the hydraulic, gear 18 is a smallelectric motor 24 under .control of a switch 24 located at any suitable point at a distance from the mill.

Upon the armature shaft 25. of the motor 24 is secured a worm 26 which meshes-with a worm wheel 27 fixed upon a followup shaft 28, the latter being supported in suit,- 5 able hearings in the brackets 29, 30, also.

, bolted to the top of the hydraulic gear 18.

In the particular example illustrated in the drawing,lthe shaft 28, which extends hori- "zontally and in parallelism with the transverse shaft '16, is screw-threaded for a portion of its length, as indicated by the ref erence character 31. The screw threaded 33 and a sprocket wheel 34, secured to the shaft 21 of the motor B, is a sprocket chain 35 for causing the nut 33 to be rotated by the rotation of the motor shaft.

The controlling member 20 of the speed gear'shown in Figs. 1 to 4- is of the type which is'reciprocated to change the inlination of the swash plate of the pump A. The

upper end of the control shaft 20 has con nected theretoa reciprocating rod 36, the lower end of which is suitably secured. to the controlling'member and the upper end of w hich slides through a bearing 37 bolted to the bracket 30. Pivotally secured to the reciprocating rod 36, as by the bolt 38 is the yoked end 39, provided at the extremity ofone arm'of a bell crank 40. The bell crank 40 is pivotally mounted as at 41 in the bracket 30 and its other arm 42 extends downwardly and terminates within a slot provided'in the follow-upshaft 28.

It will be understood that rotation of the follow-up shaft 28, b means of the electric motor 24 will, by t e engagement of the threaded portion 31 of said follow-up shaft with the threads of the nut 32,v cause the shaft 28 to be moved longitudinally of its axis, according to the direction in which it has been rotated by the electric motor 24.

This movement of the follow-up shaft will thus causing the driving shaft 21 of the motor to be rotated, and through the reducill) tion gearing 23 "and transverse shaft 16, I

producing rotation of the adjusting screws 13 of the mill. The rotation of the driving shaft 21 of the motor B is communicated through the reduction gearing, consisting of the s rockets 33, 34 and chain 35, to the nut he arrangement oft'he parts is such thatthe nut 32 will be'rotated in the same direction as the rotation of the follow-up shaft by the motor 24 as described above.

This rotation of the nut 32 in the same direction as the control-shaft 28 will obviously cause thefollowfup shaft 28 to be moved longitudinally in a direction opposite to that. produced by the rotation of the shaft by means of the electric motor 24, so that the follow-up shaft will be returned'to itsinitial position. This'longitudinal movement of the follow-up shaft in returning to its initial position will be communicated through the bell crank 40, 42 and reciprocating rod 36 to the controlling member 20,

thus returning the swash plate of the pump to its neutral position. The rotation of the nut 32 is in the nature of an overhauling movement of the parts, so that the reverse movement produced by the rotation of the nut .upon the follow-up shaft, will lag behind the movement of said shaft produced by the rotation of the motor 24. As long as the operator athis remote station holds in the switch which starts the electric motor 2%, the electric motor obviously will continue to run and the stroke of the pump will continue to be increased, but at a relatively slow rate of speed, because of the overhauling action of the nut 32, it will be obvious that as the stroke of the "pump increases, the speed of the hydraulic motor B will increase and therefore the speed of rotation of the control nut will be increased. This increase in speed of the nut 32 will continue until a point is reached where the speed of the nut and the speed ofthe follow-up shaft 28 will be the same; at this point there will be no further increase instroke on the A-end, and consequently the speed of the shaft 21 of the B-end Wlll remain constant. The speed attained by the B-end shaft before this point is reached obviously will be determined by the ratios of the various gears, and also obviously there will be a time interval or lag before the rotation of the nut 32 reaches the speed of rotation of the follow-u shaft 28. As soon as the operator of the distant control breaks the circuit to the electric motor 24, the motor will stop, and the follow-up control will bring the controlling member 20 back to neutral, thereby stopping further delivery of fluid to the motor B, and consequently stopping the rotation of the shaft 21 of said motor. As the relative movement of the adjusting screws 13 of the mill must be very small, the gear ratlos are relatively small and the movement of the B-end shaft, after the motor has stopped, is only a fraction of a turn. With an installation such .as disclosed in this application it is possibl for the operator to hold the control sw tch 'closed until the indicator device, such as is .usuallyprovided in distant controls of thls character, has indicated that the rolls have reached thedesired setting; if then the operator breaks the circuit, travel of the adjusting screws stops practically instantaneously and there is no over travel such as occurs with the electric drives heretofore commonly used.

The principles of the inventlon obviously are not limited in their application to the specific details 0f the constructional example selected for -illustration, as obviously many changes, variations and modifications of said details may be resorted to without departing from such principles.

I claim:

1. The combination with a rolling mill having co-operating rolls and adjusting screws to-vary the gap between said rolls, of

a variable speed transmission gear includingable means automatically to be moved in a.

direction opposite to that produced by said electric motor.

2. The combination with having co-operating rolls and adjusting screws to vary the gap between said rolls, of a variable speed transmission gear including a pump and motor, the latter having a rotatable driving shaft, gearing connecting said shaft and said screws, said pump having adjustable means to reverse or vary the out put thereof and thereby cause the speed or direction of rotation of said motor to be varied, an'electric motor for actuating said adjustable'means, and a follow-up device operatively associated with said rotatable driving shaft and connected with said adjustable means for automatically producing a movement of said adjustable means equal to, and opposite in direction to, that produced by said electric motor, the movement of said adjustable means produced by said follow-up device lagging behind the movement produced by said motor. 3. lhe combination with having oo-operating rolls and adjusting screws to vary the gap between said rolls, of a variable speed transmission gear including a pump and motor, the latter having a rotata le driving shaft, gearing connecting between said shaft and said screws, said pump having adjustable means to reverse or vary. the output thereof and therebyTzai-ise the speed or direction of rotation of said motor to be varied, an electric motor 'for' actuating said adjustable means, a distant control for said electric motor, a follow-up device connected with said adjustable means, and driving means from said rotatable shaft to said follow-up means for. producing a movement through said follow-up device of said adjustable means opposite indirection tothat produced by. said electric motor, the movement of said adjustable means produced by said follow-u device lagging behind the movement pro uced by said electric motor.

t. The combination with a. rolling mill a rolling mill a rolling mill I p aeraieo ing connecting said shaft and screws, said pump having an adjustablecontrol means for reversing or varying its output thereby to causethe speed or directionof rotation of said motor tobe varied, said means including a pair of rotatable members in screw threaded engagement, an electric motor for driving one of said members, a distant control for said electric motor, and driving connections between said rotatable shaft and the other of said members for causing the rotation of said shaft to produce a follow-up movement between said two members.

5. The combination with a rolling mill having eo-operating rolls and adjusting screws to vary the gap between said rolls,vof

a variable speed'hydraulic transmissiongear comprising a pump and a motor, the latter having a rotatable driving shaft, gearing connecting said shaft and screws, said pump having an adjustable control means for reversing or varying its output thereby to cause the speed or direction of rotation of I said motor to be varicd,-said means including a pair of rotatable members in screws threaded engagement, an electric motor for driving one of said members, a distant control for said electric motor, and drivingcon- "nections between said rotatable shaft and the other of said members for causing the rotation of said shaft to produce an overhauling or follow-up movement between said two members;

6; The combination with a rolling mill having co-operating rolls' and adJusting screws to vary the gap between said rolls, of

"a variable speed hydraulic transmission gear comprising a. pump and a motor, the latter having a rotatable driving shaft, gearing connecting said shaftand screws, Said pump having an adjustable control means for reversing or varying" its output thereby to cause the speed or direction of rotation of said motor to be varied, said means including a pair of rotatable members in screw threaded engagement, an electric motor for driving one of said members and producing a move- 7 ment of said adjusting means to vary or reverse the rotation of said hydraulic motor and its rotatable shaft, a'distant control for said electric motor, a'driving connection between said rotatable shaft and the other of said rotatable members vfor producing a movement of said other member in the same direction as that of said one member produced by the rotation of said electric motor thereby to neutralize the movement of said adjusting means produced by said electric motor, the neutralizin efiect produced by said other member lagging behind the movement produced by said electric motor.

In testimony whereof I have hereunto set my hand.

DANIEL a. resume. 

